The present invention relates to a wiper blade for a windscreen wiper, having a wiper strip, on which at least one loadbearing rail is arranged which has a spring element which is provided with a plastic covering, and having a base connection device which has plastic and is welded to the plastic covering.
U.S. Pat. No. 7,523,522 B2 describes a wiper blade of this type having a base connection device which has a plate-shaped carrier part with holding claws which are formed integrally thereon. The holding claws engage round associated loadbearing rails of the wiper blade at least in sections. Four cylindrical depressions are formed in the plate-shaped carrier part, into which cylindrical depressions cylindrical welding tools, what are known as rod-shaped sonotrodes, can be introduced in order to weld the base connection device to the loadbearing rails by means of ultrasonic welding. Said rod-shaped sonotrodes make punctiform welding of the loadbearing rails to the holding claws and the underside of the plate-shaped carrier part in the region of the cylindrical depressions possible.
A disadvantage of said prior art is that the welding takes place only at four predefined welded points and is therefore problematic in the event of the occurrence of shear forces in a direction along the loadbearing rails. Moreover, the punctiform shape of a weld of this type prevents optimum transmission of the forces of a corresponding wiper arm to a wiper strip which is assigned to the wiper blade and therefore to the wiper lip of said wiper strip. In particular, this shape of the weld has a negative influence on the bearing force distribution of the wiper lip on an associated pane, which bearing force distribution is decisive for a desired wiping result.